Actually, there is no infinitive form for can in English (no to can), except in the transitive verb sense.

In the example Josseppe gave, can might have a more immediate connotation (i.e., I can ride a bike to get to your house, as opposed to walking), while am able to clearly refers to knowing how to ride a bike in general.

Nello stesso modo, "to be able to" può essere usato con altri verbi modali, come "will, would" ecc
Eg
I will be able to finish the project if I have more time.
I would be able to finish the project if I had more time.

When we talk about a specific, one-time achievement in the past, we use was or were able to. We do not use could.
Talia was able to finish Sunday’s crossword puzzle in just an hour.
We do not say, She could finish Sunday’s crossword puzzle in just an hour.

We can use couldn't or wasn't (or weren't) able to to talk about past inability, including specific, one-time events.
Talia entered a crossword contest last year. But she wasn’t able to finish the puzzle.
She couldn’t figure out one of the words.

For all other forms and tenses we use be able to, not can or could. We use it after to for the infinitive, with the present perfect, and with the future.
Talia hopes to be able to give Tony an answer soon.